I think you mean 90C... 90F = 32C = The temp we all wish our cards would run at 24/7.

As for the lifespan, not entirely sure, I haven't killed a card yet (knock on wood) though I manage to keep mine comfortably in the 70s and 80s.

I use stock coolers on the cards themselves but as it happens I already had a portable AC unit hooked up to my living room window so I just blow cold air directly into the intakes. These can be had for under $300 and I'd consider them to be a good investment if you want to mine long-term without replacing a lot of cards.

it actually says 32c so i was assuming that was estimated to 90 degrees f

Is it submerged in mineral oil inside of a mini-fridge? That's phenomenal if you're talking temperature under load. The rig closest to the AC unit is still in the 60s for me. Then again I do live in Vegas and it did break 100F today

Personally, I'm running a mineral oil computer with an attached chiller, and I'm maintaining about 55C on my GTX 470's (its a gaming rig, only started on bitcoins recently) while mining. I got into computer cooling as a hobby several years ago, and have played with liquid cooling, mineral oil, and mechanical chilling. From what I understand, every 10C over 50C you roughly halve the lifetime of the component in question, though I don't know what the normal expected life of a well cooled card is.

If you're maintaining 90F on a card while mining, I'd be astonished. I don't know how you'd manage that without some serious phase-change equipment.

Personally, I'm running a mineral oil computer with an attached chiller, and I'm maintaining about 55C on my GTX 470's (its a gaming rig, only started on bitcoins recently) while mining. I got into computer cooling as a hobby several years ago, and have played with liquid cooling, mineral oil, and mechanical chilling. From what I understand, every 10C over 50C you roughly halve the lifetime of the component in question, though I don't know what the normal expected life of a well cooled card is.

If you're maintaining 90F on a card while mining, I'd be astonished. I don't know how you'd manage that without some serious phase-change equipment.

I don't get how that could be true when most modern GPU's I've dealt with have idled over 60C... do you have a source for that?